Sunday, 23 February 2014

A quick look at the other tools

After this weekend there will be two
more before election day. Last weekend we covered the maps of
electoral trends, which leaves us with the seat run-downs and
pendulum to discuss. It might seem like a good idea to dedicate this
weekend to one, next weekend to the other and the final weekend to
formalising predictions. However, next weekend I will be providing
summaries of each Legislative Council party. While this is not useful
in regards to predicting electoral outcomes I personally believe it
is one of the most important subjects I cover on this blog since it
helps people make informed above- or below-the-line votes, provides
links to each parties website and just generally makes the whole
process easier. I know I had a few of my non-regular readers visit my
blog exclusively for those summaries.

The Polls and the Pendulum

This week, then, we will cover both the
seat rundowns and the pendulum. For the latter we will be using
Antony Green'sdata
as opposed to the numbers produced by the South Australian Electoral
Districts Boundaries Commission. You can read the important
distinctions at the previous link, but basically Antony Green's data
is for psephological purposes while the EDBC's is for the
redistribution of boundaries and factors in all kinds of demographic
shifts. As Mr Green himself explains, “when calculating swing, you
should be comparing with the 2010 election, not a mythical estimate
of what the 2010 result might have been in 2014.”

Notice that the above pendulum is
sorted alphabetically instead of by margin or party? You won't see a
pendulum like that from anyone who actually knows what they are
doing. Here, however, it is useful because we can directly cross
reference the pendulum seat-by-seat with our other tools. However,
for the purists or those more visually inclined, here is the same
information of a Liberal-Labor scale.

Note that the Independents in
Fisher, Frome and Mount Gambier are listed as Liberals

The Independents have been included
with the Liberals on this scale for several reasons. Firstly, their
margins are all measured against the Libs, so the Labor party is well
down in a 3-horse race. Secondly, the Independents are conservative,
suggesting that a lot of their votes would flow to the Libs if they
did not run. This means that the Labor vote in these seats is not
necessarily low because would-be Labor voters were seduced by the
lure of an Independent (although it is a fair be that a lot of the
Labor vote flowed to the Independents rather than the Libs and
probably cost the Coalition the seat. Thirdly, in a hung parliament,
it is expected the Independents would side with the Liberal Party to
form government.

Although the Labor Party has more seats
(and hence is currently in power), the Liberals fewer marginal seats:
3 (and an Independent) compared with Labor's 11. The Liberals only
have one fairly safe seat (and an Independent) compared to Labor's 4,
and while Labor has 11 safe seats the Liberals have 10, plus 1
Independent and 4 in the very safe category which Labor failed to
reach. If the Liberals won all of Labor's marginals, they would hold
29 seats with 3 Independents by their side; if Labor won all of the
Liberal marginals they would hold 29 seats with 3 Independents
against them.

Assuming a uniform swing and support
from the Independents, the Liberals need a 0.6% swing in their favour
(which, if repeated in the Independent contest in Mount Gambier would
also win them that seat. Even without the support of the greys,
Steven Marshall would form a government on the back of a uniform 2.6%
swing. Whether or not they will get this swing, of course, remains to
be seen.

Seat Statistics

Swings, of course, are not uniform,
although the search for a reliable indicator of where they will be
stronger or weaker continues to allude me. Instead we are going to
have to rely on seats being “Labor seats” and “Liberal seats”
to calculate which seats are most open to being targeted. Previous
analysis indicates that a seat that has a large swing one election
might have a small swing the next, so such definitions can only be a
rough guide at best.

Previously for the run downs I
interpreted each seat on two factors – how strongly it supported a
party (its “strength”) and how reliable that support was (its
“volatility”). The former was subjectively assigned as very safe,
safe or leaning, while the latter was intuitively divided into
stable, variable and volatile. These assignments were based on the
incumbency and margin (provided above in the pendulum) and the seat's
history outlined last weekend. One additional factor used in the
federal election – the state seats that lie within the federal
seats – cannot be replicated at the state level.

This election we are going to try
something different. For the purposes of making the results
repeatable, consistent and measurable, these run downs will rely on
more rigid definitions.

The VDTAs are useful for examining
recent voting trends. The run downs attempt to identify long-term
biases in seats. For this reason, historical inclination will be
determined from the number of times a party has won the seat but lost
the election – that is, where the seat's preferences are revealed
to be skewed to one party or another relative to the state as a
whole.

To do this, we first need to know the
results of every election since 1938:

The following districts voted against
the general trend in the following years:

From this we can calculate the
following tables:

For simplicity we have ignored
Independents. The contrary count is the number of times the seat has
been won by a party that lost the election. Adelaide has voted for
the ALP 11 times when the Coalition has gone on to win the election,
which initially suggests this is a decent seat for Labor.

The In Step table shows how many times
the seat has been won by the party that also won the election. This
is useful because it lets us total the number of times a party has
won the seat; realising that Playford has voted for the ALP 4 times
in Coalition victories is somewhat meaningless until we also realise
it has never voted for the Coalition.

The final table is calculated to show
the percentage of times the ALP has won Coalition elections and vice
versa. In Adelaide, Labor won the seat in 11 of the 12 Coalition-won
elections (91.7%) and the Coalition won Adelaide in 3 of the 10 Labor
elections (30%) since 1938. ALP data fro Little Para cannot be
calculated because it has never participated in a Coalition-won
election. No figures for Mount Gambier can be calculated since it has
always elected an Independent.

Let's calculate the liability of each
seat to favour a given party from the difference between these last
figures. To continue to use Adelaide as an example, lets say the seat
is 91.7 – 30 = 61.7% leaning to the ALP. Like most of the dramatic
ALP leans, this is mostly historical, with a large opposition to the
Coalition dominance prior to 1965 under the Playford-favouring
Gerrymander creatively known as the Playmander. However lets leave
the concerns about recent vs ancient trends to be picked up by the
VDTAs and use this (admittedly arbitrarily calculated) figure for a
ballpark and see what we can kick around.

I have also arbitrarily assigned leans
of more than 66.66% the label “steadfast”, those over 33.33%
“Reliable” and the rest “Leaning” (with the two previously
mentioned exceptions of Little Para and Mount Gambier). This was not
done simply because dividing the range into three equal-sized
divisions is appealing. I subjectively assigned the labels to the
seats and checked their values later. These values are close
approximations of my intuitive divisions of the seats:

Adelaide: Reliable Labor

Ashford: Steadfast Labor

Bragg: Steadfast Liberal

Bright: Reliable Liberal

Chaffey: Reliable Liberal

Cheltenham: Steadfast Labor

Colton: Leaning Labor

Croydon: Steadfast Labor

Davenport: Steadfast Liberal

Dunstan: Reliable Labor

Elder: Reliable Labor

Enfield: Steadfast Labor

Finniss: Steadfast Liberal

Fisher: Steadfast Liberal

Flinders: Steadfast Liberal

Florey: Steadfast Labor

Frome: Leaning Liberal

Giles: Steadfast Labor

Goyder: Steadfast Liberal

Hammond: Steadfast Liberal

Hartley: Leaning Labor

Heysen: Steadfast Liberal

Kaurna: Reliable Labor

Kavel: Steadfast Liberal

Lee: Reliable Labor

Light: Steadfast Liberal

Little Para:Unknown

MacKillop: Steadfast Liberal

Mawson: Leaning Labor

Mitchell: Steadfast Labor

Morialta: Reliable Liberal

Morphett: Steadfast Liberal

Mount Gambier:Unknown

Napier: Steadfast Labor

Newland: Leaning Liberal

Playford: Steadfast Labor

Port Adelaide: Steadfast Labor

Ramsay: Steadfast Labor

Reynell: Reliable Labor

Schubert: Steadfast Liberal

Stuart: Steadfast Liberal

Taylor: Steadfast Labor

Torrens: Reliable Labor

Unley: Leaning Labor

Waite: Steadfast Liberal

West Torrens: Steadfast Labor

Wright: Reliable Labor

Exactly how this factors into the final
results will have to wait until the predictions, but here is a quick
look at the data:

On face value it looks as though the
ALP has the slight majority in an even battle, but the Coalition only
needs to break into the Labor Leaning seats to take a majority.
Colton, Hartley, Mawson and Unley are seats to watch. Particularly
Unley – a recurring oddball.

By and large this data conforms with
the current state of the seats, which suggests a decent predictive
power. Ignoring the unknowns (Little Para is Labor while Mount
Gambier is Independent) and the Liberal-leaning Independents (Frome
and Fisher are still listed as Liberal seats), there are only 3 seats
from each party that have a supposed bias contrary to their current
incumbent – Adelaide, Dunstan and Unley are currently Liberal while
Bright, Light and Newland are currently Labor. These, again, will be
worth watching. Again, particularly Unley.

Finally their historical inclination
calculated here also closely correlate with the VDTA. All of the
clear Liberal or Labor seats on the VDTA correspond with Liberal or
Labor seats from today's data, with the single exception of the
oddball Unley (again!) which is historically safe Liberal on the VDTA
but leaning Labor here.

Fisher is slightly closer to grey than
the other blue seats, but is still Liberal by both measures. The
VDTA's slightly red Morialta is listed as reliable Liberal here, but
the colour is so close to the midrange on the map I don't see this as
a major disagreement. The other mid-ranged seats on the VDTA are as
follows:

Hartley and Mawson – leaning Labor

Newland – leaning Liberal

Bright – Reliable Liberal

Light – Steadfast Liberal

Note that these last three – Bright,
Light and Newland – are the three peculiarities listed above as
Labor occupied but (by this post's reckoning) Liberal inclined.
Either today's analysis has failed to capture a recent development in
these seats, or the atypical Labor incumbency has biased the VDTA.
All have passed to Labor for the last two elections after at least 4
wins by the Coalition, which could support either interpretation.

Either way, in the wider view, all of
our methods are starting to align nicely.